A surface acquisition system typically comprises a plurality of cameras, projectors, or lasers that can reconstruct a 3D surface model of an object using stereovision techniques, structured illumination or structured light techniques, or time-of-flight techniques. The generated 3D surface model has applications in conjunction with X-ray imaging. For example, the 3D surface characterization can be used as prior information for more accurate acquisition planning, dose estimation, and scatter estimation. In addition, real time 3D surface characterization can be used for detecting and compensating patient motion during image acquisition. 3D surface characterization can be particularly useful for correlation with radiography data where the x-ray imaging apparatus forms a volume image, such as a tomosynthesis image or CBCT image, for example.
Both the surface acquisition system and the X-ray imaging system are preferably calibrated before use. Typically, calibration is viewed as tedious and time-consuming, often without providing the accuracy needed where both surface characterization and volume imaging systems are used. In conventional practice where surface acquisition supports X-ray imaging, each system is separately calibrated, independently of the other system. Typically, for example, the two systems use different calibration phantoms. In addition, there appear to be no phantom solutions that allow calibration of the transformation parameters between surface acquisition and radiography systems.
Thus, with respect to imaging apparatus that combine the benefits of surface characterization with radiography imaging, there is a need for a phantom configured to: (i) calibrate the surface acquisition system (e.g., extrinsic and intrinsic calibration parameters of the cameras, projectors, or lasers); (ii) calibrate the X-ray imaging system (including geometric parameters of the X-ray tube and detector at different rotation angles); and (iii) calibrate the transformation parameters (e.g., rotation and translation) for registering spatial points between these two systems.
The background above is provided for general overview information and is not intended to be used as an aid in determining the scope of the claimed subject matter. The invention is defined by the claims.